Hi Benny, Thank you for your comments. Yes, I think that a diplexer in front of the pre-filter and and a 5dB amplifier after it would work. I do not have the necessary test equipment here to show the before and after results, so I will probably wait until someone like yourself (or Elecraft) makes those modifications. To date I have found no IMD problems caused by the Pre-filter, but there again I am not resident in a country where we are 'legally' allowed to run kW's.
73 Stewart G3RXQ On Mon, 21 Mar 2005 20:27:44 +0200, Benny Aumala wrote: > > > Dear OM Steward, > how about using a diplexer in front of prefilter. > If impedance there is 150 ohms, try 4,86uH and 213pF combination. > If not, I would like to simulate other impedances. > Between prefilter and 2N5109 amplifier this could save the 5dB attenuator > loss for > prefilter. > Looking components, the hi-Q coils are not necessary, but care must be taken > to > choose a ferrite without IMD. I am looking for 15mm tubes of Siferrit U17. > That is a component very hard to find now. But 30 years ago I made the best > minimum-loss > bandfilters with them. _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
